Technical Field
This description generally relates to the acquisition of material features.
Background
The angular and wavelength dependency of light incidence and reflection for a single ray of light on the surface of a material is described by the spectral bidirectional reflectance distribution function (BRDF). An extension of BRDF for modeling the appearance of non-uniform surfaces is given by the bidirectional texture function (BTF), which includes non-local scattering effects like inter-reflections, subsurface scattering, and shadowing.